Hello, and thanks for checking out this cruise blog. My name is Brendan Carter and I am one of several bloggers for this cruise. I'm sailing this time as the Co-chief scientist, which means I am in charge of making sure great science gets done, the data gets collected and reported, and everything goes smoothly... especially when Chief Scientist Lynne Talley is off watch. I say 'this time' because I got my start in cruise work as a chemistry technician while working on my doctoral dissertation.
I'll preface this by apologizing for the unimaginative formatting. We are submitting these updates from the Southern Ocean, and internet bandwidth is a precious commodity. We will do what we can! Without further ado...
I'll preface this by apologizing for the unimaginative formatting. We are submitting these updates from the Southern Ocean, and internet bandwidth is a precious commodity. We will do what we can! Without further ado...
about 7 days to go before we get onto the main P16S line. The P16S line
is one of a global network of lines of waypoints at which the
oceanographic community routinely measures seawater properties from the
surface to the ocean floor. We are looking for the chemical and physical
imprints of global change. P16S goes north-south along 150° W from ~67°
S to about 15° S. It has been measured twice before, once in 1991 and
once in 2005. This cruise will go into work overdrive when we get onto
the line, and we'll stay that way for another 37 days.
We passed under the Tasman Bridge over the Derwent River in Hobart in
the evening on March 20. We waited until after rush hour since the
Tasmanians stop all bridge auto traffic when ships pass under, a
precaution started after a ship tragically hit the bridge some years
ago. We passed Macquarie Island earlier today, getting a push from the
powerful Antarctic Circumpolar Current. At the moment, we're steaming
southeast just along the Australian/New Zealand EEZ boundary.
We have four important float deployments with accompanying water sample
profiles to do before we get to P16S. We estimate that we'll be in
position for the first one―on a 'P14S' waypoint recently measured (in
2012) by a Japanese research expedition―in the afternoon on the 26th of
March. That gives us about two days more steaming to get all of our
metaphorical ducks happily quacking in a row.
We are using the time judiciously. Many groups have been cutting their
freshly re-assembled instruments' teeth on junk seawater, or making
measurements for the underway sampling program. Our analysts have been
measuring discrete underway samples for alkalinity, total dissolved
inorganic carbon, pH, nitrate, phosphate, silicate, and oxygen. Our
sensors are also continuously reporting partial pressure of CO2,
temperature, and salinity from the surface, Acoustic Doppler Current
Profiling down to 1000-2000 m, bathymetry, and meteorological sampling.
The students who will be working with the marine technicians to deploy
the rosette package are scheduled for communications training tomorrow,
and have been helping prepare the samples that we will be collecting for
groups without any direct representation aboard.
Our first station will see the deployment of a biogeochemical Argo
float. This float has been outfitted with ice avoidance software and
sensors for oxygen, nitrate, and bio-optics in addition to the standard
sensors for conductivity, temperature, and pressure. We will collect a
full profile of each of these quantities from the rosette― focusing on
the 2000 m depth range of the float― to intercompare with the first
float profile. The robotic float will collect its first ascending
profile ~12-16 hours after our first cast. We expect that it will then
go on to measure hundreds more profiles as it bobs from 2000 m to the
surface in a pre-programmed cycle, returning the data it collects to
scientists on land by satellite. Eventually its batteries will die, and our
proud robot will get a well-earned rest.
The rosette package has been equipped with sensors for conductivity,
temperature, oxygen (2 sensors), and pressure (on the CTD), a Lowered
Acoustic Doppler Current Profiler (LADCP), a transmissometer, a
fluorometer, a set of thermistors recording temperature microstructure
(Chi-POD), and an altimeter to keep the package from crashing into the
bottoa... our last sample will only be 10 m above the ocean floor. The
rosette will bring back water that we will then pounce on and sample for
up to 19 different analytical procedures. We are working to carefully
budget the water to ensure that all groups get what they need, with
water priorities as laid out in the CLIVAR plan that laid our entire
program out.
In between logistical meetings, we've been having daily science
meetings. We've had four people give presentations already, and have a
rough plan for 8 more talks, 2 software tutorials, and a host of 'lab
visits' between our various analysts in the days to come.
Chief Scientist Lynne Talley is crunching numbers for our time budget
to see whether we can contribute an extra station or two to our original
plan. It would be wonderful to sample more of the southernmost reaches
of the Antarctic Circumpolar Current.
Discussions of time have become increasingly complex. Our
computer clocks are set to the local time wherever we came from. Our
personal time pieces are mostly set to local time in Tasmania. Most
scientific operations are conducted in GMT. Complicating things
further, we'll cross several timezones and gain a day when we cross
the international date line in a couple of days. We're trying to make
plans that depend on how efficient we are, how long weather will keep us
from collecting seawater, and even how much extra speed we'll pick up
from following the strong westerly currents in the Southern Ocean.
We're making great time right now, in part because we have the wind of a
storm system at our backs.
Veronica Tamsitt, blogger extraordinaire, has organized an exercise
competition designed to keep us fit and un-complacent with our workout
routines as the cruise goes on… and on. And on. The challenge will be
stark, for the Palmer has good and plentiful food. Today's birthday
cake for Adam Radich came on the heels of pizza, cookies, and burritos
yesterday.
Mostly, we are very much looking forward to losing ourselves in the
blur of deploying a rosette package every 6-8 hours, though having time
for daily science meetings has been a luxury indeed.
